Environmental Effects of Tidal Energy Outcomes of a Scientific Workshop Brian Polagye

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Environmental Effects of Tidal EnergyOutcomes of a Scientific Workshop

Brian PolagyeUniversity of Washington

Northwest National Marine Renewable Energy Center

PICES 2010October 26, 2010

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Environmental Effects Workshop Overview Challenges Recommendations

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Tidal Energy Devices

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“Typical” Sites and Devices

2-4 m/s

20-60 m

Foundation

Drive TrainRotor

5-20 m 10-30 rpm

Gearbox-Generator

Direct Drive Generator

Pile Gravity Base

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Environmental Stressors

Device presence:Dynamic effects

Device presence:Static effects

Electromagnetic effects

Acoustic effects

Chemical effects

Energy removal

Cumulative Effects

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Environmental Receptors

Near-field environment

Far-field environment

Ecosystem Interactions

Benthic habitat

Pelagic habitat

Marine mammals

Fish (migratory and resident)

Seabirds

Invertebrates

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Environmental Assessment Framework

Boehlert, G. and Gill, A. Environmental and Ecological Effects of Ocean Renewable Energy Development, Oceanography, 2010

Level 1

Level 2

Level 3

Level 4

Level 5

Type of Marine Renewable Energy

Stressors

Receptors

Level 6

Environmental Effect (frequency and duration)

Environmental Impact (type and severity)

Cumulative Effects (scales and context)

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Environmental Effects Workshop Overview Challenges Recommendations

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Need for Workshop

Major interest in developing hydrokinetic energy in the U.S.

Environmental compatibility of technology stated without proof.

Environmental uncertainties present a major barrier to projects getting in the water at any scale.

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Technology Scope

Tidal Hydrokinetics Tidal Barrage River Hydrokinetics

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Geographic Scope

Coastal Maine

Puget Sound

Southeast Alaska

Cook InletAleutian Islands

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Session Chairs Discussion4 hours

Receptors2.5 hours

Stressors1.5 hours

Wrap Up1.5 hours

Plenary Sessions4 hours

Stressors2.5 hours

Workshop Structure

Day 1

Day 2

Day 3

Participant Feedback: Another day would have been useful

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Workshop Participants

US West Coast (CA, OR, WA, AK)

US East Coast

Europe

Canada

Universities

Agencies/NGOs

Research Labs

Industry

Specific technical or scientific expertise Representative distribution of affiliation Interest greatly exceeded capacity

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Relative Significance and Uncertainty

Physical environment:Near-field

Physical environment:Far-field

Habitat and Invertebrates

Fish: migratory

Fish: resident

Marine Mammals and Seabirds

Ecosystem Interactions

Stressor element #1

Stressor element #2

… Color denotes significance

Environmental receptor

Stressor element

LowMediumHigh

Unknown

Not Applicable

Symbol denotes uncertainty

?

LowMediumHighUnknown

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Presence of Devices – Static Effects

Physical environment:Near-field

Physical environment:Far-field

Habitat &Invertebrates

Fish: migratory

Fish: resident

Marine Mammals & Seabirds

Ecosystem Interactions

Structure below water surface

Structure above water surface

Disturbances from installation of device

Disturbances from installation of power cable

Disturbances from removal of device

Disturbances from removal of power cable

Maintenance

Pilot Scale

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Presence of Devices – Static EffectsCommercial Scale

Physical environment:Near-field

Physical environment:Far-field

Habitat &Invertebrates

Fish: migratory

Fish: resident

Marine Mammals & Seabirds

Ecosystem Interactions

Structure below water surface

Structure above water surface

Disturbances from installation of device

Disturbances from installation of power cable

Disturbances from removal of device

Disturbances from removal of power cable

Maintenance

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Identification of Priority Interactions Selection Criteria

—High potential significance

—High uncertainty

Summarize Key Information—Description

—Gaps in Understanding

—Monitoring Approaches

—Mitigation Measures (stressor only)

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Workshop Report

Will be published as NOAA Tech Memo

Draft out for review to participants by end of week

Details of breakout sections Challenges indentified Recommendationshttp://depts.washington.edu/nnmrec/workshop

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Environmental Effects Workshop Overview Challenges Recommendations

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Project Environmental Data are Scarce

Single device5 m diameterInstallation

effects only

CleanCurrent

Single device2 x 16 m diameterAcoustic effectsMarine mammal

behaviorSeabird behaviorBenthic habitat

MCT

Single device6 m diameterAcoustic effectsFish behaviorBenthic habitat

Open Hydro

Array5 m diameterFish behaviorSeabird behaviorBenthic habitat

Verdant Power

Single device3m diameter*Acoustic effectsMarine mammal

behaviorFish behavior

ORPC

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Information Needs at Pilot ScaleStressor Priority

AreaBefore Pilot During Pilot

Presence of devices: static effects

Effects of static structures on benthic ecosystems

Characterize benthic habitat.Characterize species presence/absence and behavior.

Disruptions to benthic habitat installation/recovery.Rate at which structures are colonized.Fish and marine mammal interactions with modified benthic ecosystems.

Presence of devices: dynamic effects

Potential for direct interactions of marine species with turbine rotor

Characterize movements of marine mammals, fish, and seabirds at temporal and spatial scales required to assess potential for direct interactions.

Types of interactions and at what frequency they occur.

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Information Needs at Pilot ScaleStressor Priority Area Before Pilot During PilotChemical effects Approaches to

preventing biofouling are poorly defined

Assess potential impacts of anti-fouling biocides.

Fate of chronically released biocides.

Acoustic effects Behavioral responses to increases in broad band noise

Behavioral response of species to acoustic signals.

Measurements of sound pressure levels from device operation.

Electromagnetic effects

Electromagnetic fields from operating and idle devices

Laboratory studies of electric and magnetic fields.Models of electric and magnetic fields from proposed devices.

Measurements of magnetic fields from energized cables and operating devices.

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Challenges to “Deploy and Monitor” Monitoring technologies are underdeveloped

—Existing methods focused on population effects

—Existing methods may not function in tidal energy environments

Difficulty of predicting, detecting, and attributing changes to tidal energy devices

Legal protections or ethical considerations prohibit studies of some interactions

Some important effects can only be measured at commercial scale

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Environmental Effects Workshop Overview Challenges Recommendations

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Preliminary Research Prioritization

Marine mammal-device interactions

—Blade strike—Acoustic effects

Fish-device interactions

Environmental tipping points for energy removal

7 receptors

x

≈6 elements

x

7 stressors

x

≈ 6 elements

≈ 1700 potential

interactions

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Pilot Projects are Required

Recognized need by participants of all affiliation

Must be well-monitored Prioritize objectives Use common protocols

Courtesy of Marine Current Turbines

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Develop Assessment Capabilities Close monitoring instrumentation gaps

—Detect, classify, and identify marine organisms at a variety of scales

—Real-time monitoring for decision making

General monitoring protocols—Objective of data collection—Type of data to be collected—Mechanisms for data collection

Numerical models—Turbine scale: hydrodynamics, fish interactions—Regional scale: tipping points

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Mitigate Impacts when PossibleStressor Priority Area Recommended MitigationPresence of devices: static effects

Effects of static structure on benthic ecosystems

Minimize anchor sizes.Minimize number of moorings and slack lines.Streamline support structures.

Presence of devices: dynamic effects

Potential for direct interactions of marine species with turbine rotor

Increase visibility of rotors to fish.Acoustic avoidance measures.Shock absorbers on leading edges of blades.Temporary device shutdown.

Electromagnetic effects

Behavioral disruption from electric and magnetic fields

Bury power cables.Twist cores for AC cables.Run DC cables of opposing polarity in close proximity.

Cumulative effects

Effects on large, mobile species

Limit number of devices at a given location until effects of operation are sufficiently understood.

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Collaboration is Essential Information needs to be shared between

projects—IEA-OES Annex IV—Significant intellectual property concerns

Hydrokinetic industry needs to engage with the oceanographic community

—Leverage active areas of research

Expand opportunities for interdisciplinary collaboration

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Acknowledgements Workshop organizing committee

— Andrea Copping, Pacific Northwest National Laboratory— Keith Kirkendall, NOAA Fisheries— George Boehlert, Oregon State University— Michelle Wainstein, University of Washington— Sue Walker, NOAA Fisheries— Brie Van Cleve, Pacific Northwest National Laboratory

Workshop sponsors—NOAA Fisheries—US Department of Energy

Workshop participants, particularly session chairs and note takers